A convicted conman has been questioned as part of an ongoing investigation into the murder of Macleay Island grandmother Liselotte Watson.

The 85-year-old widow was found dead in the bedroom of her Macleay Island home on November 13 after her friend and local delivery man Steven Fennell asked police to check on her when he could not reach her.

An autopsy confirmed Mrs Watson, who was described by family and friends as a good natured, generous woman, had fallen victim to a vicious attack.

Detective Inspector Gerry Costello would not confirm on Friday whether police have a suspect in their sights.

"We're pursuing a number of lines of inquiry," he said.

Inspector Costello said investigators had worked "tirelessly around the clock" on the case throughout the holiday season.

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"Investigations have now extended to New South Wales, Victoria, South Australia and Tasmania in order to follow up some promising leads in the case," he said.

Mr Fennell was convicted of theft in 1985 and spent the following year behind bars in Tasmania.

After he was released, he told The Sunday Tasmanian of fraudulent conquests, estimating he had fleeced at least three businesses of $250,000, including Australia Post and the TAB.

"I am not a saint, I am a conman, I am into fraud and I have done lots of unscrupulous things," he told the newspaper in November 1986.

"But I have never hurt a private citizen."

When Mr Fennell was contacted by Fairfax, he said: "Under legal advice I am unable to comment (about the Macleay Island murder case)."

Born in Brisbane, Mr Fennell reportedly worked as a council health inspector before moving to Tasmania.

In 1986, Mr Fennell also told the newspaper he was "trying to go straight", but had been unable to find work and was struggling on the dole.

One man sympathised with Mr Fennell's plight and responded to the newspaper article.

Mr Chaplin understands Mr Fennell returned to Queensland after the business was sold in 1988, but hadn't heard from him until six months ago.

"He rang me to say hello and told me he was living on Macleay Island," Mr Chaplin said.

In unrelated evidence, last November police revealed a shaving bag containing bank books belonging to Mrs Watson was found washed up on Dalpura Beach, near Thompson's Point on Macleay Island, the weekend before Mrs Watson died.

The bag had been weighed down with a rock and thrown into the sea, police said.

Police divers later recovered more items belonging to Mrs Watson in waters off Thompsons Point, but have refused to reveal what else was found.

"It would appear whoever is responsible for this may have visited [Thompsons Point] a number of times and deposited these items from the murder scene on a couple of occasions," Detective Superintendent Geoff Sheldon told reporters at the time.

Many of the items discovered have since been sent to the Victorian Institute of Forensic Medicine for thorough DNA testing.

Police have also engaged a forensic accounting firm to trawl through Mrs Watson's financial records and examine her spending habits, since the 85-year-old was known to hoard cash at her home.

Mrs Watson lived alone on the island, but spoke regularly to her daughter and granddaughter. She last spoke to her family the day before she was found dead.

Why such a "lovely lady" became the victim of a brutal, fatal attack in the sanctity of her own home remains a mystery that has shocked police and the island community.

It is understood Mr Fennell had befriended Mrs Watson and would often visit her home to have tea and run errands for her on the mainland.

Police have asked for anyone who may have seen anything untoward on Macleay Island in the two weeks before November 13 to call Crime Stoppers on 1800 333 000 or crimestoppers.com.au.